1 



Plate IX. 



(All the specimens are in the collection of the Museum of Comparative 

 Zoology at Cambridge. The illustrations are reduced.) 



Pa(;e. 

 Figs. 1-7. ClaviUthcs rngosus. typical forms of various ages (1380, 1380, 



1374. 1 125, 1 125, 1 125, 1380) 105 



8. Clavilithcs rugosus. coarse variety with distant ribs (1413) loS 



9-12. Rhopalithes rugoides, typical forms showing protoconch and 



columellar plications (27776, 27-777, 27776, 2777^) ' 135 



13. Cosmolithcs uniplicatus (1133) 142 



14-17. Rhopalithes angulatus, shells of various ages (1384 (3). 1385)- •• 136 

 18 and 19. Rhopalithes sp., young specimens, probably R. nocc, in the 



subtuberculoides stage (1131) 138 



20. Cosmolithes uniplicatus (27782) 142 



21. Rhopalithes angulatus, gerontic form ( 13S2 ) 137 



22. Rhopalithes clavelloides (type), a phylogerontic type of the R. 



angulatus series (1393) I37 



2T, and 24. Rhopalithes tuberculoides ( 27784, 27728, type) 138 



(174) 



